Message-Id: <20250601232435.3507697-13-sashal@kernel.org>
Date: Sun,  1 Jun 2025 19:22:55 -0400
From: Sasha Levin <sashal@...nel.org>
To: patches@...ts.linux.dev,
	stable@...r.kernel.org
Cc: Anusha Srivatsa <asrivats@...hat.com>,
	Maxime Ripard <mripard@...nel.org>,
	Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
	Tejas Vipin <tejasvipin76@...il.com>,
	Doug Anderson <dianders@...omium.org>,
	Neil Armstrong <neil.armstrong@...aro.org>,
	Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>,
	Sasha Levin <sashal@...nel.org>,
	maarten.lankhorst@...ux.intel.com,
	tzimmermann@...e.de,
	airlied@...il.com,
	simona@...ll.ch,
	dri-devel@...ts.freedesktop.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH AUTOSEL 6.15 013/110] drm/panel/sharp-ls043t1le01: Use _multi variants

From: Anusha Srivatsa <asrivats@...hat.com>

[ Upstream commit 20e8219205145e1af3b98b6a0a3cc59568116a05 ]

Move away from using deprecated API and use _multi variants
if available. Use mipi_dsi_msleep() and mipi_dsi_usleep_range()
instead of msleep() and usleep_range() respectively.

Used Coccinelle to find the _multi variant APIs,replacing
mpi_dsi_msleep() where necessary and for returning
dsi_ctx.accum_err in these functions. mipi_dsi_dcs_write()
does not have a corresponding _multi() variant. Replacing it with
mipi_dsi_dcs_write_seq_multi() instead. This change is manual.

The Coccinelle script is the same as the one in commit c8ba07caaecc
("drm/panel/synaptics-r63353: Use _multi variants")

v2: Use mipi_dsi_write_buffer_multi() in place of
mipi_dsi_dcs_write(). (Dmitry)

v3: add commit details where the same coccinelle script is
used and remove the actual script from commit log.
Use mipi_dsi_dcs_write_seq_multi() for mipi_dsi_dcs_write() (Doug)

Cc: Maxime Ripard <mripard@...nel.org>
Cc: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
Cc: Tejas Vipin <tejasvipin76@...il.com>
Cc: Doug Anderson <dianders@...omium.org>
Signed-off-by: Anusha Srivatsa <asrivats@...hat.com>
Reviewed-by: Neil Armstrong <neil.armstrong@...aro.org>
Reviewed-by: Douglas Anderson <dianders@...omium.org>
Link: https://lore.kernel.org/r/20250326-b4-panel-ls043t1le01-v3-1-96c554c0ea2b@redhat.com
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---

Looking at this commit, I need to analyze whether it should be
backported to stable kernel trees. **Answer: NO** **Detailed Analysis:**
This commit is a **code modernization/refactoring change** that converts
from deprecated MIPI DSI APIs to newer "_multi" variants. Here's my
detailed reasoning: ## 1. **Nature of Changes - API Modernization Only**
The changes are purely about replacing deprecated function calls with
their modern equivalents: - `mipi_dsi_dcs_exit_sleep_mode()` →
`mipi_dsi_dcs_exit_sleep_mode_multi()` -
`mipi_dsi_dcs_set_pixel_format()` →
`mipi_dsi_dcs_set_pixel_format_multi()` -
`mipi_dsi_dcs_set_display_on()` → `mipi_dsi_dcs_set_display_on_multi()`
- `mipi_dsi_dcs_write()` → `mipi_dsi_dcs_write_seq_multi()` - `msleep()`
→ `mipi_dsi_msleep()` This is classic API modernization, not a bug fix.
## 2. **No Functional Bug Fixes** The commit doesn't address any user-
visible issues, crashes, security vulnerabilities, or hardware
compatibility problems. The panel functionality remains identical - this
is purely about using preferred APIs for better error handling patterns.
## 3. **Pattern Consistent with Similar Commits** All the reference
commits provided show the same pattern and are marked as **"Backport
Status: NO"**: - **Similar Commit #1**: "Switch to
mipi_dsi_dcs_write_seq_multi()" - mechanical conversion for code
reduction - **Similar Commit #2**: "add more multi functions" - adding
new API variants and deprecating old ones - **Similar Commit #4**:
"Transition to mipi_dsi_dcs_write_seq_multi" - replacing deprecated
macros - **Similar Commit #5**: "use mipi_dsi_dcs_nop_multi()" -
removing conditional code using multi wrappers All these similar commits
involve the same type of API modernization and none were backported. ##
4. **Error Handling Changes Don't Fix Existing Bugs** While the new
"_multi" pattern provides better error handling through
`dsi_ctx.accum_err`, the original code was already handling errors
properly with explicit return checks. The change improves code
maintainability but doesn't fix any error handling bugs. ## 5. **Stable
Tree Criteria Violation** This commit violates stable tree rules: -
**Not a critical bugfix**: No user-impacting issues resolved -
**Introduces new features**: Uses newer API variants that may not exist
in older kernels - **Code churn without necessity**: Changes working
code for style/modernization reasons - **Potential compatibility
issues**: "_multi" variants may not be available in all stable branches
## 6. **Risk vs. Benefit Analysis** - **Risk**: Potential
incompatibility with older kernel versions, unnecessary code churn -
**Benefit**: None for stable users - no bugs fixed, no new functionality
for end users ## **Conclusion** This is a textbook example of a commit
that should **NOT** be backported to stable trees. It's pure code
modernization that doesn't fix any user-visible problems, follows the
same pattern as other non-backported similar commits, and could
potentially introduce compatibility issues in stable branches. Stable
trees should only receive critical fixes, not API modernization changes.

 .../gpu/drm/panel/panel-sharp-ls043t1le01.c   | 41 +++++++------------
 1 file changed, 15 insertions(+), 26 deletions(-)

diff --git a/drivers/gpu/drm/panel/panel-sharp-ls043t1le01.c b/drivers/gpu/drm/panel/panel-sharp-ls043t1le01.c
index 729cbb0d8403f..36abfa2e65e96 100644
--- a/drivers/gpu/drm/panel/panel-sharp-ls043t1le01.c
+++ b/drivers/gpu/drm/panel/panel-sharp-ls043t1le01.c
@@ -36,60 +36,49 @@ static inline struct sharp_nt_panel *to_sharp_nt_panel(struct drm_panel *panel)
 static int sharp_nt_panel_init(struct sharp_nt_panel *sharp_nt)
 {
 	struct mipi_dsi_device *dsi = sharp_nt->dsi;
-	int ret;
+	struct mipi_dsi_multi_context dsi_ctx = { .dsi = dsi };
 
 	dsi->mode_flags |= MIPI_DSI_MODE_LPM;
 
-	ret = mipi_dsi_dcs_exit_sleep_mode(dsi);
-	if (ret < 0)
-		return ret;
+	mipi_dsi_dcs_exit_sleep_mode_multi(&dsi_ctx);
 
-	msleep(120);
+	mipi_dsi_msleep(&dsi_ctx, 120);
 
 	/* Novatek two-lane operation */
-	ret = mipi_dsi_dcs_write(dsi, 0xae, (u8[]){ 0x03 }, 1);
-	if (ret < 0)
-		return ret;
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xae,  0x03);
 
 	/* Set both MCU and RGB I/F to 24bpp */
-	ret = mipi_dsi_dcs_set_pixel_format(dsi, MIPI_DCS_PIXEL_FMT_24BIT |
-					(MIPI_DCS_PIXEL_FMT_24BIT << 4));
-	if (ret < 0)
-		return ret;
+	mipi_dsi_dcs_set_pixel_format_multi(&dsi_ctx,
+					    MIPI_DCS_PIXEL_FMT_24BIT |
+					    (MIPI_DCS_PIXEL_FMT_24BIT << 4));
 
-	return 0;
+	return dsi_ctx.accum_err;
 }
 
 static int sharp_nt_panel_on(struct sharp_nt_panel *sharp_nt)
 {
 	struct mipi_dsi_device *dsi = sharp_nt->dsi;
-	int ret;
+	struct mipi_dsi_multi_context dsi_ctx = { .dsi = dsi };
 
 	dsi->mode_flags |= MIPI_DSI_MODE_LPM;
 
-	ret = mipi_dsi_dcs_set_display_on(dsi);
-	if (ret < 0)
-		return ret;
+	mipi_dsi_dcs_set_display_on_multi(&dsi_ctx);
 
-	return 0;
+	return dsi_ctx.accum_err;
 }
 
 static int sharp_nt_panel_off(struct sharp_nt_panel *sharp_nt)
 {
 	struct mipi_dsi_device *dsi = sharp_nt->dsi;
-	int ret;
+	struct mipi_dsi_multi_context dsi_ctx = { .dsi = dsi };
 
 	dsi->mode_flags &= ~MIPI_DSI_MODE_LPM;
 
-	ret = mipi_dsi_dcs_set_display_off(dsi);
-	if (ret < 0)
-		return ret;
+	mipi_dsi_dcs_set_display_off_multi(&dsi_ctx);
 
-	ret = mipi_dsi_dcs_enter_sleep_mode(dsi);
-	if (ret < 0)
-		return ret;
+	mipi_dsi_dcs_enter_sleep_mode_multi(&dsi_ctx);
 
-	return 0;
+	return dsi_ctx.accum_err;
 }
 
 static int sharp_nt_panel_unprepare(struct drm_panel *panel)
-- 
2.39.5

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